Fluorescence light microscopy is a core technique in life sciences that has contributed to countless major discoveries. However, the diffraction limit, first described by Ernst Abbe in 1873 [1]}, has restricted the optical resolution to about half the wavelength of the light used, i.e. 200-300 nm in the lateral directions (x and y), and to about the wavelength of light, i.e. 500-800 nm along the optical axis (z). In the past two decades, several super-resolution microscopy (SRM) approaches have been developed that allow to overcome this barrier and push the spatial resolution to the 10-100 nm range, thus closing the gap to electron microscopy [2]}, [3]}, [4]}. The SRM techniques can be further divided into single-molecule localisation microscopy (SMLM) [5]}, that includes techniques like photoactivatable localisation microscopy (PALM) [6]}, [7]} and stochastic optical reconstruction microscopy (STORM) [8]}, stimulated emission depletion (STED) [9]}, [10]}, [11]} microscopy and structured illumination microscopy (SIM) [12]}, [13]}. In recognition of these breakthrough developments Eric Betzig, Stefan Hell and William E. Moerner were awarded the Nobel prize for Chemistry in 2014 [14]}.
